Postanoxic Myoclonic Seizures After Pediatric Cardiac Arrest: Characteristics and Outcomes in a Single-Center Cohort, 2018-2024.

OBJECTIVES

To describe clinical features and outcomes among children with postanoxic myoclonic seizures (PAMS) after cardiac arrest (CA).

DESIGN

Retrospective cohort.

SETTING

Single-center, children's hospital in the United States.

PATIENTS: Patients younger than 18 years old with in- or out-of-hospital CA with PAMS identified on video continuous electroencephalography (CEEG) within 24 hours of CA (2018-2024).

INTERVENTIONS: None.

MEASUREMENTS AND MAIN

RESULTS

Twenty-six children with in-hospital or out-of-hospital CA and PAMS, defined as clinical myoclonus with electrographic correlates, were identified from a CA database. PAMS was verified on video CEEG. Median (interquartile range [IQR]) age was 6.3 years (IQR, 1.1-11.9 yr). Baseline Pediatric Cerebral Performance Category (PCPC) was 1 (normal) for 17 children. PAMS were observed within 1 hour of CEEG initiation for 19 children and within 12 hours for all children. PAMS manifested as limb jerking (18/25) and rhythmic eye opening (13/25). The range in electroencephalography (EEG) background was continuous (1/26), discontinuous (2/26), burst-suppressed/burst-attenuated (20/26), and entirely suppressed (3/26). Bursts were often highly epileptiform (15/20) and identical (10/20). All patients received at least 1 anti-seizure medication, and 16 of 26 received at least 1 anesthetic infusion. Death before hospital discharge occurred in 17 of 26, and causes of death were withdrawal of life-sustaining therapy (10/17), brain death (6/17), and rearrest (1/17). Among nine survivors, PCPC scores ranged from 3 to 5, eight had gastrostomies, and one a tracheostomy. A brain MRI was available for 15 of 26 at a median 4 days (IQR, 3-5 d) after CA. All had restricted diffusion involving the precentral and postcentral gyri and cortex supplied by the posterior cerebral artery. The one child with moderate disability (PCPC = 3) at hospital discharge had continuous EEG background and limited MRI diffusion restriction.

CONCLUSIONS

Children with PAMS have a range of EEG characteristics. Severe disability and death were common following PAMS. The child with moderate disability had a continuous EEG background and limited MRI diffusion restriction.